Dynamo-electric machine



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H. K. WHITE-:HORN

DYNAMO ELECTRIC MACHINE Filed Augusta, 1924 I VE/770i lil Patented Feb. 2, 1926.

UNIT ST ATE PA 'E ENT' OQFLF'ILCE HAROLD KENNETH WHITEHORN, or iaarns'ronn ENQLAND, AssIeNon To TILLING- STEVENS morons LiMrTnn, on MarnsToNn, ENGLAND.

DYNAMO-ELECTRIG MACHINE.

Application filed August 6, 1924.

To, all whom imag conce/m.'

lie it known that Hnkonn KENNETH lifnirnrroizN, a.l British suloject7 residing at ll'llonbridge Road, Maidstone, Kent England, has invented certain new and useful Improvements in Dynamo-Electric Machinesa of which the following is a specification.

rlfhis. inventionl relates to dynamo electric machines. An Objectis to provide a` light and ei'iicient construction of uni-directional machine-i. e. a machine in which the relative direction olf rotationef field and armature. (whether either one or both be designed to rotate) is normally or at maximum load in a predetermined direction as opposed to a machine intended to run indiiferently i. either direction.

Another object is to counteract the uneven distribution of the magnetism on the pole face due to armature reaction, which, as well known, tends on load to decrease the flux` `on the leading pole tip in a generator; the distortion in a motor is 'in the opposite direction.

It has been proposed to overcome this by the use of various arrangements of series windings disposed, for example, in notches in the pole face.

The present invention is concerned with machines of t-he kind in which the field magnet poles are divided into magnetically separated (or substantially so) portions, a yoke portion extending between the adja cent portions of adjacentl poles; the field magnet thus in effect consists of a number of separate magnets with like poles adja* cent to one another, each pair of like poles forming a single field magnet pole.

The present invention comprises in such a machine a field magnet built up as described characterized in that one section of each pole-i. cwone limb of each of the constituent magnets-is provided with a series winding spanning that limb alone for the purpose of maintaining sulostantiall;7 uniform distribution of the fiux on the pole face in spite of armature reaction when the machine comes under load.

The invention further comprises in such a machine a field magnet consisting' of n'iagnets having one pole of comparatively large sectional area and one of comparatively small sectional area, one large and one small pole of adjacent magnets (herein Serial No. 730,488.

after for convenience called pole-sections) forming each main pole. of the field magnet the small` pole-section being woundfi with the series winding tending to compensate tor armature reaction, by strengthening-.the held where it would normally be ,weakened` tached to or integral witlrthe yoke between` pole-sections. Preferably these are` ein ployed in the form in which each magnet includes large and a small pole-sectiontnel connnutating pole being of the same polarity as the small pole-section.

The invention further comprises` the novell features, combinations and arrange,- ments which are embodied in the preferred forms hereinafter described and are specilically claimed.

Referring to the accompanying drawing.I a preferred form of field construction is shown comprising a number of similar laminated magnets mounted in a nonn'iagnetic frame.

As illustrated the complete field magnet is built up of laminated magnets each provided with a pole-section a of comparatively large area and a pole-section of comparatively small. area connected by a yoke portieri c, the yoke portion being correspondingly reduced in area on the side nearer to the small pole-section. is shown it is definitely stepped adjacent to the interpole;v but particularly where no interpoles are used it mayY rather be of somewhat tapering form. The magnets are assembled in a frame d which forms no essential part of the magnetic circuit and consistingr` as shown, of a thin cast alu minium ring Z1 formed with appropriate strengthening ribs (Z2, intermediate packing pieces f which may be of non-magnetic material heilig provided. A shunt (or series) winding (1 spans each pole and in addition there is a series Winding h on each all pole-section a, each of these latter pole-sections being provided with a detachable shoe to facilitate assembly (or the coil being of sutic-ient size to be slipped over the pole-tips). Commutating poles 7c with suitable windings m are possible additions in this construction: one such pole is indicated in the drawing.

It Will be noted that the stepped arrangement oi' the yoke adjacent to the interpole suitably proportions the areas of the yoke and pole-sections leading to the respective pole faces.

The term series7 coil or Winding is to be understood throughout to include a coil carrying either the whole or a portion oit' the main current. j

It will be understood that pole tips may be employed ot' unsymmetrical form in linown manner to assist in correct distribun tion ot the pole liuX.

l'claim:-

l. A dynamo-electric machine having a ield magnet including the combination of a plurality of magnets each having one pole of comparatively large and one of comparatively small sectional area, a large pole and a small pole from adjacent magnets forming two separate sections of each main pole of the complete field magnet and a series winding spanning each small pole section.

2. A dynamo-electric machine having a ield magnet including the combination of a plurality of magnets magnetically separated from one another, each of said mag-- nets comprising two poles and a connecting yoke portion7 the arrangement being such that one pole from each of two adjacent magnets torms a section of each main pole of the complete tield magnet and a. series winding spanning one pole alone of each of the constituent magnets.

3. A dynamo-electric machine having a ield magnet including the combination of a plurality of constituent magnets each comprising three poles, the two outer poles forming sections of adjacent main poles of the machine and the intermediate pole forming an interpole, the proportions being such that the sectional area of one outer pole is substantially equal to the combined sectional yareas of the second outer pole andl the intermediate pole.

Il. A dynamo-electric machine having a field magnet including the combination of a plurality ot constituent magnets each comprising a yoke portion and three poles7 the tiro outer poles forming sections of adjacent main poles of the machine and the intern'iediate pole forming an interpole, the proportions being such that the sectional area ot' one outer pole is substantially equal to the combined sectional areas of the second outer pole and the intermediate pole and the yoke portion being stepped adjacent to the interpole so as to leave a smaller sectional area of yoke leading to the smaller of the outer poles.

In testimony whereof l alix my signature.

HAROLD KENNETH WHITEHORN. 

